Service Hotline2. Low cycle fatigue Low cycle fatigue means that the fatigue stress is close to or exceeds the yield limit of the material. The material has a certain amount of plastic deformation in each strain cycle. The life is generally in the range of 102 to several times 104, and the fatigue curve is generally used. ε-N curve representation. The finite element calculation results show that after the bolt is screwed into the lock nut, the stress at the root of the threaded piece is large, and part of the surface area is in a yield state, while the strain in the central area of the root of the threaded piece is small, and the strain situation is more complicated. The area with high strain at the root of the thread piece experiences reciprocating loading, which is prone to low cycle fatigue, which reduces the pressure of the thread piece and reduces the screw-out torque.
1. Correctly select the product a. Before use, confirm whether the mechanical properties of the product can meet the needs of use, such as the tensile strength of the screw and the guaranteed load of the nut. The length of the screw should be selected appropriately, and the 1-2 pitch of the nut will be exposed after tightening. b. Before use, check whether the threads are rough, and whether there is iron filings or dirt between the threads, which often lead to locking. c. The fasteners can be lubricated before use. It is recommended to use butter, molybdenum disulfide, mica, graphite or talc for lubrication. Generally, dipping wax is used for lubrication and anti-locking. [1] 2. Pay attention to the use method when using it. a. The speed and force of screwing in should be appropriate, not too fast or too large. Use a torque wrench or socket wrench as much as possible, and avoid using an adjustable wrench or an electric wrench. Excessive speed will cause the temperature to rise rapidly and cause lock-up. b. In the direction of force, the nut must be screwed in perpendicular to the axis of the screw. c. The use of washers can effectively prevent the problem of over-tightening.
The commonly used tools for fixing screws on the surface of the workpiece are electric screwdrivers and manual screwdrivers. Both of these screwdrivers manually attach the screws to the bits of the electric screwdriver or manual screwdriver, and then fix the screws on the surface of the workpiece. The screwdriver is inefficient in fixing the screw, and cannot accurately locate the screw fixing point.
At present, the industry uses the pure manual installation method to install the elastic cylindrical pin, that is, the staff first holds the tool holder; then, manually puts the elastic cylindrical pin into the elastic cylindrical pin hole of the tool holder; then, use the body to align the tool holder For positioning, use a hammer to knock the elastic cylindrical pin into the tool holder. This installation method requires manual operation throughout the entire process, and the work efficiency is low. Moreover, when the hammer is knocked, the staff needs to use the body to position the tool holder, there is a risk of smashing and injuring people, and there is a potential safety hazard. In addition, hammering will cause deformation of the elastic cylindrical pin, and the qualification rate of assembly is low.
Embedding of fasteners, especially screws. The main point of the structure is that it includes an annular base, one at the base and a plurality of cylindrical tubes on the base, and the cylindrical tubes and the cylindrical tubes on the base are connected by ribs. Cylindrical tubes are used as fixing holes and fastener pre-embedded holes respectively. The product is fixed on the formwork that needs to use screw points through the fixing holes. After the concrete is poured into the floor, the embedded screw parts are pre-embedded, and the floor has embedded screw holes for hanging the installation objects with screws. . Avoid future re-drilling damage to the wall and floor. Guangdong Yueluo Hardware Industry Co., Ltd. has a simple and scientific structure, easy pre-embedding, strong tensile strength and firmness.
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